Fix arranging unprintable objects

fixes #10911
fixes SPE-1830

src/libslic3r/Arrange/Core/ArrangeItemTraits.hpp

@@ -93,6 +93,11 @@ template<class ArrItem> bool is_fixed(const ArrItem &ap)
     return get_bed_index(ap) >= PhysicalBedId;
 }
 
+template<class ArrItem> bool is_on_physical_bed(const ArrItem &ap)
+{
+    return get_bed_index(ap) == PhysicalBedId;
+}
+
 template<class ArrItem> void translate(ArrItem &ap, const Vec2crd &t)
 {
     set_translation(ap, get_translation(ap) + t);

src/libslic3r/Arrange/Core/NFP/RectangleOverfitPackingStrategy.hpp

@@ -19,6 +19,36 @@ struct CenterAlignmentFn {
     }
 };
 
+template<class ArrItem>
+struct RectangleOverfitPackingContext : public DefaultPackingContext<ArrItem>
+{
+    BoundingBox limits;
+    int bed_index;
+    PostAlignmentFn post_alignment_fn;
+
+    explicit RectangleOverfitPackingContext(const BoundingBox limits,
+                     int bedidx,
+                     PostAlignmentFn alignfn = CenterAlignmentFn{})
+        : limits{limits}, bed_index{bedidx}, post_alignment_fn{alignfn}
+    {}
+
+    void align_pile()
+    {
+        // Here, the post alignment can be safely done. No throwing
+        // functions are called!
+        if (fixed_items_range(*this).empty()) {
+            auto itms = packed_items_range(*this);
+            auto pilebb = bounding_box(itms);
+
+            for (auto &itm : itms) {
+                translate(itm, post_alignment_fn(limits, pilebb));
+            }
+        }
+    }
+
+    ~RectangleOverfitPackingContext() { align_pile(); }
+};
+
 // With rectange bed, and no fixed items, an infinite bed with
 // RectangleOverfitKernelWrapper can produce better results than a pure
 // RectangleBed with inner-fit polygon calculation.
@@ -29,31 +59,7 @@ struct RectangleOverfitPackingStrategy {
     PostAlignmentFn post_alignment_fn = CenterAlignmentFn{};
 
     template<class ArrItem>
-    struct Context: public DefaultPackingContext<ArrItem> {
-        BoundingBox limits;
-        int bed_index;
-        PostAlignmentFn post_alignment_fn;
-
-        explicit Context(const BoundingBox limits,
-                         int bedidx,
-                         PostAlignmentFn alignfn = CenterAlignmentFn{})
-            : limits{limits}, bed_index{bedidx}, post_alignment_fn{alignfn}
-        {}
-
-        ~Context()
-        {
-            // Here, the post alignment can be safely done. No throwing
-            // functions are called!
-            if (fixed_items_range(*this).empty()) {
-                auto itms = packed_items_range(*this);
-                auto pilebb = bounding_box(itms);
-
-                for (auto &itm : itms) {
-                    translate(itm, post_alignment_fn(limits, pilebb));
-                }
-            }
-        }
-    };
+    using Context = RectangleOverfitPackingContext<ArrItem>;
 
     RectangleOverfitPackingStrategy(PackStrategyNFP<Args...> s,
                                     PostAlignmentFn post_align_fn)
@@ -89,6 +95,19 @@ struct PackStrategyTraits_<RectangleOverfitPackingStrategy<Args...>> {
     }
 };
 
+template<class ArrItem>
+struct PackingContextTraits_<RectangleOverfitPackingContext<ArrItem>>
+    : public PackingContextTraits_<DefaultPackingContext<ArrItem>>
+{
+    static void add_packed_item(RectangleOverfitPackingContext<ArrItem> &ctx, ArrItem &itm)
+    {
+        ctx.add_packed_item(itm);
+
+        // to prevent coords going out of range
+        ctx.align_pile();
+    }
+};
+
 template<class Strategy, class ArrItem, class Bed, class RemIt>
 bool pack(Strategy &strategy,
           const Bed &bed,

src/libslic3r/Arrange/Tasks/ArrangeTaskImpl.hpp

@@ -54,6 +54,20 @@ std::unique_ptr<ArrangeTask<ArrItem>> ArrangeTask<ArrItem>::create(
     return task;
 }
 
+// Remove all items on the physical bed (not occupyable for unprintable items)
+// and shift all items to the next lower bed index, so that arrange will think
+// that logical bed no. 1 is the physical one
+template<class ItemCont>
+void prepare_fixed_unselected(ItemCont &items, int shift)
+{
+    for (auto &itm : items)
+        set_bed_index(itm, get_bed_index(itm) - shift);
+
+    items.erase(std::remove_if(items.begin(), items.end(),
+                               [](auto &itm) { return !is_arranged(itm); }),
+                items.end());
+}
+
 template<class ArrItem>
 std::unique_ptr<ArrangeTaskResult>
 ArrangeTask<ArrItem>::process_native(Ctl &ctl)
@@ -78,8 +92,15 @@ ArrangeTask<ArrItem>::process_native(Ctl &ctl)
 
     } subctl{ctl, *this};
 
-    arranger->arrange(printable.selected, printable.unselected, bed, subctl);
-    arranger->arrange(unprintable.selected, unprintable.unselected, bed, ctl);
+    auto fixed_items = printable.unselected;
+
+    // static (unselected) unprintable objects should not be overlapped by
+    // movable and printable objects
+    std::copy(unprintable.unselected.begin(),
+              unprintable.unselected.end(),
+              std::back_inserter(fixed_items));
+
+    arranger->arrange(printable.selected, fixed_items, bed, subctl);
 
     // Unprintable items should go to the first bed not containing any printable
     // items
@@ -89,6 +110,10 @@ ArrangeTask<ArrItem>::process_native(Ctl &ctl)
     // If there are no printables, leave the physical bed empty
     beds = std::max(beds, size_t{1});
 
+    prepare_fixed_unselected(unprintable.unselected, beds);
+
+    arranger->arrange(unprintable.selected, unprintable.unselected, bed, ctl);
+
     result->add_items(crange(printable.selected));
 
     for (auto &itm : unprintable.selected) {